船舶反渗透海水淡化水矿化钙适宜浓度分析

Research on the proper calcium concentration for shipboard seawater reverse osmosis remineralizafion

目的探讨船舶反渗透淡化水矿化钙的适宜浓度。方法通过对成人钙的营养摄入来源、钙对淡化水腐蚀指数的影响、船舶反渗透淡化水的矿化方法，以及相关水质标准的分析，从多角度提出船舶反渗透淡化水矿化钙适宜浓度，再利用我国城市饮用水水质进行验证。结果膳食是人体钙的主要来源。钙能降低反渗透淡化水的腐蚀性，但当增加至41 mg/L时贡献明显降低。船舶反渗透淡化水适合采用药剂法矿化，常用矿化剂氯化钙的最大允许使用量为36 mg/L（以钙离子浓度计）。从健康方面考虑，现有标准一般要求软水矿化钙在16 mg/L以上。结论船舶反渗透淡化水矿化钙适宜浓度为16-36 mg/L，我国57%的城市饮用水钙浓度在此范围内。

ObjectiveTo research and propose the proper calcium concentration for shipboard seawater reverse osmosis remineralization.MethodsComprehensive analyses were made on the calcium nutrient intake of adults, the effects of [Ca^2＋ ] level on the desalination corrosion index, the methods of shipboard seawater reverse osmosis remineralization and related remineralization criteria. Then, the range of proper calcium concentration of soft water remineralization was recommended for shipboard seawater reverse osmosis remineralization from different angels, which was verified by municipal drinking water quality survey results.ResultsFood was the main source of human calcium intake. [Ca^2＋ ] concentration elevation could significantly reduce the corrosiveness of desalinated water, however, the contribution ratio for Langelier index （LSI）was debased when [Ca^2＋ ] reached 41 mg/L. Shipboard desalination remineralization was more preferable with direct added agential. At present, for the sake of health, the minimum quality criteria for [Ca^2＋ ] in soft water was 16 mg/L. Calcium chloride was commonly used for desalinated water remineralization, with the maximum permitted concentration being 36 mg/L. ConclusionsIn consideration of the shipboard environment and support capability comprehensively, the applicable calcium concentration of shipboard RO desalination remineralization was 16-36 mg/L, which was within the range of drinking water calcium concentration for 57% of the cities of our countries.